"
I can't sleep, cause my mind keeps racing
My chest hurts cause my heart keeps breaking
I'm so numb and I can't stop shaking
And we all fall down
I'm not 100% with this, but my theory is that they are in a lot of stress and can't stop thinking about whatever is stressing them out. It could be girls, the fans, it could even be the music that they want to get done with to keep their dream going. It's hard to tell if you observe the lyrics throughout the song. It's still great! Can't wait to get the album.